Perceived prosodic typicality in Finnish preadolescents: Findings from speakers on the autism spectrum

Speech of persons on the autism spectrum is often described as prosodically distinctive, yet the perceptual basis and acoustic correlates of these judgements remain undefined. We investigated how prosodic typicality is perceived in low-pass filtered speech from Finnish-speaking preadolescents on the autism spectrum and matched controls, and how these perceptions relate to acoustic features. A total of 53 listeners rated 150 utterances for typicality and provided written comments. Mixed-effects modelling revealed no significant effect of diagnostic group on perceived typicality; instead, individual listener variability predominated. Acoustically, speakers on the autism spectrum exhibited greater pitch range, intensity range and frequent pausing. However, only select acoustic measures predicted typicality ratings, regardless of speaker group. Analysis of listener comments emphasised the salience of intonation and voice quality to typicality perceptions. These findings suggest that perceived prosodic typicality may not be a direct marker of neurodivergence but rather reflect the interaction of specific acoustic configurations and listener expectations.